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3 years ago

Please help !! Brainliest if correct?

Chemistry

1 answer:

Hitman42 [59]3 years ago

3 0

Answer:

All of these stoichiometry problems are worked alike. Here is the 4 step process.

4Na + O2 → 2Na2O

Step 1. Write and balance the equation. You have that.

Step 2. Convert whatever you have to mols. If a solid then mols = grams/molar mass = ?. If a solution then mols = M x L = ? In this case, the molar mass of Na2O is approx 62 so mols = 2/62 = approx 0.03 but that's just a close guess. You should do it more accurately.

Step 3. Using the coefficients in the balanced equation, convert mols of what you have to mols of what you want. You have mols Na2O and you want to convert that to mols Na.

0.03 mols Na2O x (4 mols Na/2 mols Na2O) = about 0.06. Note that mols Na2O in the numeratorof the first term cancels with mols Na2O in the denominator of the second term which leaves mols Na which is what you want. In practice you ALWAYS know that the coefficient of the unit you are converting to goes on top and the coefficient of mols you have goes on the bottom.

4. Now convert mols of what you want to grams. grams = molsl x molar mass - about 0.06 x 23 = about ?

Copy this. It can come in handy for every chemistry course you take.

Explanation:

You might be interested in

How many molecules of carbon dioxide are dissolved in 0.550 L of water at 25 °C if the pressure of CO2 above the water is 0.250

Grace [21]

Answer: The number of molecules of carbon dioxide gas are $2.815\times 10^{21}$

Explanation:

To calculate the molar solubility, we use the equation given by Henry's law, which is:

$C_{CO_2}=K_H\times p_{CO_2}$

where,

$K_H$ = Henry's constant = $0.034mol/L.atm$

$C_{CO_2}$ = molar solubility of carbon dioxide gas

$p_{CO_2}$ = pressure of carbon dioxide gas = 0.250 atm

Putting values in above equation, we get:

$C_{CO_2}=0.034mol/L.atm\times 0.250atm\\\\C_{CO_2}=8.5\times 10^{-3}M$

To calculate the number of moles for given molarity, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}$

Molarity of carbon dioxide = $8.5\times 10^{-5}M$

Volume of solution = 0.550 L

Putting values in above equation, we get:

$8.5\times 10^{-3}M=\frac{\text{Moles of }CO_2}{0.550L}\\\\\text{Moles of }CO_2=(8.5\times 10^{-3}mol/L\times 0.550L)=4.675\times 10^{-3}mol$

According to mole concept:

1 mole of a compound contains $6.022\times 10^{23}$ number of molecules

So, $4.675\times 10^{-3}$ moles of carbon dioxide will contain = $(6.022\times 10^{23}\times 4.675\times 10^{-3})=2.815\times 10^{21}$ number of molecules

Hence, the number of molecules of carbon dioxide gas are $2.815\times 10^{21}$

3 0

3 years ago

Read 2 more answers

Consider the following isotopic abundance data for argon (Ar) and silicon (Si):

pshichka [43]

Answer:

Explanation:

Molar mass of Argon

= 35.96755 x .00337 + 37.96272 x .00063 + 39.96240 x .99600

= .12121 + .0239165 + 39.80255

= 39.95

Molar mass of silicon

27.97693 x .9223 + 28.97649 x .0467 + 29.97376 x .0310

= 25.803 + 1.35320 + .929

= 28.08

b )

No of atoms of Si in 78.2 g = 78.2 x 6.02 x 10²³ / 28.08

= 16.76 x 10²³ .

c )

42 Ar / 40 Ar = 1.05006

42 Ar / 39.95 = 1.05006

42Ar = 41.95

2 )

C₁₆H₁₅F₂N₃O₄S

Mol weight = 16 x 12 + 1 x 15 + 2 x 19 + 3 x 14 + 4 x 16 + 32

= 192 + 15 + 38 + 42 + 64+ 32

= 383

No of molecules = .078 x 6.02 x 10²³ / 383

= 1.226 x 10²⁰ molecules .

7 0

3 years ago

The equilibrium of 2H 2 O(g) 2H 2 (g) + O 2 (g) at 2,000 K has a Keq value of 5.31 x 10-10. What is the Keq expression for this

maks197457 [2]

Answer is: Keq expression for this system is Keq = [O₂ ] · [H₂]² ÷ [H₂O]².
Chemical reaction: 2H₂O(g) ⇄ O₂(g) + 2H₂(g).
The equilibrium constant (Keq) is a ratio of the concentration of the products (in this reaction oxygen and hydrogen) to the concentration of the reactants (in this reaction water).

7 0

4 years ago

Write a balanced chemical equation for the reaction that occurs when heptane, C7H16(l) , burns in air.

Pavlova-9 [17]

Start with Unbalanced Equation and balance it, so...
C7H16+O2--->CO2+H2O
There are 7 C atoms on the left-hand side, so we need 7 C atoms on the right-hand side. Add a 7 in front of the CO2...7CO2+H2O on right side now.
We have fixed 16 H atoms on the left-hand side, so we need 16 H atoms on the right-hand side. Add an 8 in front of H2O to make 16 (8x2)...7CO2+8H2O on right side now.
There are 22 O atoms on the right-hand side: 14 from the CO2 and 8 from the H2O. Add an 11 in front of the O2 on the left side to make 22 (11x2).
Every formula now has a fixed coefficient. You should have a balanced equation of...
C7H16+11O2--->7CO2+8H2O

8 0

3 years ago

2CO + O2 → 2002

Reika [66]

Answer:

B: Increasing the volume inside the reaction chamber

Explanation:

5 0

4 years ago